Lighting system with lens assembly

ABSTRACT

According to at least one aspect, a lighting device is provided. The lighting device comprises a circuit board, a light emitting diode (LED) mounted to the circuit board and configured to emit light, a lens disposed over the LED having a bottom surface facing the circuit board, a top surface opposite the bottom surface, and a lateral surface between the top and bottom surfaces, and an elastomer encapsulating at least part of the circuit board. The elastomer may not be in contact with at least part of the lateral surface of the lens so as to form a gap between the elastomer and the lateral surface of the lens.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.17/230,534 filed on Apr. 14, 2021, which is a continuation of U.S.application Ser. No. 16/161,221 filed on Oct. 16, 2018 and issued onJun. 1, 2021 as U.S. Pat. No. 11,022,279, which is a continuation ofU.S. application Ser. No. 15/453,842, filed Mar. 8, 2017 and issued onNov. 20, 2018 as U.S. Pat. No. 10,132,476, which claims the benefitunder 35 U.S.C. § 119(e) of each of the following: U.S. ProvisionalApplication Ser. No. 62/305,386, filed on Mar. 8, 2016, U.S. ProvisionalApplication Ser. No. 62/405,446, filed on Oct. 7, 2016, U.S. ProvisionalApplication Ser. No. 62/405,456, filed on Oct. 7, 2016, U.S. ProvisionalApplication Ser. No. 62/405,463, filed on Oct. 7, 2016, U.S. ProvisionalApplication Ser. No. 62/405,468, filed on Oct. 7, 2016, and U.S.Provisional Application Ser. No. 62/405,472, filed on Oct. 7, 2016. Eachof the above-identified applications is hereby incorporated herein byreference in its entirety.

BACKGROUND

Light emitting diodes (LEDs) are typically formed from a semiconductormaterial that is doped to create a p-n junction. The LEDs typically emitlight in a narrow spectrum (e.g., a spectrum that is smaller 100nanometers in size) that is dependent upon the bandgap energy of thesemiconductor material that forms the p-n junction. For example, an LEDformed using one semiconductor material may emit light of a differentcolor (and thereby in a different spectrum) than an LED formed usinganother semiconductor material.

White light has a broad spectrum (e.g., a spectrum that is larger than200 nanometers in size), unlike the light typically emitted from an LED.White light may be formed by mixing light with different colors (andthereby different spectrums) together. For example, white light may beformed by mixing red, green, and blue light or blue and yellow light.Inexpensive LEDs that create white light (a white LED) typically use anLED configured to emit blue light (a blue LED) that is coated with ayellow phosphor. The yellow phosphor coating converts a portion of theblue light from the LED into yellow light. The mixture of the blue andyellow light forms white light.

SUMMARY

According to at least one aspect, a lighting device is provided. Thelighting device comprises a circuit board, a light emitting diode (LED)mounted to the circuit board and configured to emit light, a lensdisposed over the LED having a bottom surface facing the circuit board,a top surface opposite the bottom surface, and a lateral surface betweenthe top and bottom surfaces, and an elastomer encapsulating at leastpart of the circuit board. The elastomer may not be in contact with atleast part of the lateral surface of the lens so as to form a gapbetween the elastomer and the lateral surface of the lens.

In some embodiments, the circuit board is a printed circuit board suchas an FR4 printed circuit board. In some embodiments, the circuit boardmay comprise multiple layers. In some embodiments, the circuit board maybe a flexible circuit board.

In some embodiments, the lighting device further comprises a reflectorhaving a reflective surface that faces the lateral surface of the lensand is disposed between the elastomer and the lateral surface of thelens (e.g., in the gap). In some embodiments, at least part of thereflective surface is configured to provide specular reflection. In someembodiments, at least part of the reflective surface is configured toprovide diffusive reflection. In some embodiments, a surface of thereflector opposite the reflective surface contacts the elastomer. Insome embodiments, a surface of the reflector opposite the reflectivesurface does not contact the elastomer. In some embodiments, thereflective surface is configured to reflect at least some light from thelateral surface of the lens back into the lens.

In some embodiments, at least part of the bottom surface of the lenscontacts the circuit board. In some embodiments, the elastomer does notcontact at least part of the top surface of the lens. In someembodiments, the gap is an air gap.

In some embodiments, the gap is at least partially filled with amaterial that is separate and distinct from the elastomer. In someembodiments, the material has a lower refractive index than the lens.

In some embodiments, the lens comprises a recess configured to receivethe LED and provide an air gap between a surface of the LED throughwhich light is emitted and the lens. In some embodiments, the lightingdevice further comprises a light scattering element disposed in therecess between the surface of the LED through which light is emitted andthe lens. In some embodiments, the scattering element comprises aplurality of scattering particles dispersed in a material. In someembodiments, the scattering particles comprise titanium dioxide (TiO₂)and the material comprises silicone.

In some embodiments, the LED is a phosphor converted LED that emitslight with an angular correlated color temperature (CCT) deviation. Insome embodiments, the lens is configured to receive the light emittedfrom the phosphor converted LED and reduce the angular CCT deviation ofthe light received from the phosphor converted LED. In some embodiments,the LED is a white phosphor converted LED configured to emit white lightwith an angular CCT deviation.

In some embodiments, the lighting device further comprises a basemounted to the circuit board. In some embodiments, the lens is coupledto the base. In some embodiments, the elastomer comprises silicone. Insome embodiments, the lens comprises silicone, glass, and/or plastic.

In some embodiments, the lighting device is configured to mount to aguide rail or a walking path to illuminate the walking path. In someembodiments, the lighting device is configured to mount to a ceiling ora ledge to illuminate at least one member selected from the groupconsisting of: a ceiling, a wall, and a billboard.

According to at least one aspect, a lighting device is provided. Thelighting device comprises a circuit board, an LED mounted to the circuitboard and configured to emit light, a lens disposed over the LED andhaving a bottom surface facing the circuit board, a top surface oppositethe bottom surface, and a lateral surface between the top and bottomsurfaces, a reflector having a reflective surface that faces the lateralsurface of the lens without contacting at least part of the lateralsurface of the lens so as to form a gap, and an elastomer encapsulatingat least part of the circuit board.

In some embodiments, the reflector comprises a surface opposite thereflective surface. In some embodiments, the elastomer contacts at leastpart of the surface of the reflector opposite the reflective surface. Insome embodiments, the elastomer does not contact at least part of thesurface of the reflector opposite the reflective surface.

In some embodiments, the gap is an air gap. In some embodiments, the gapis at least partially filled with a material. In some embodiments, thematerial in the gap has a lower refractive index than the lens.

According to at least one aspect, a lighting device is provided. Thelighting device comprises a circuit board, an LED mounted to the circuitboard that is configured to emit light with an angular CCT deviation, alens assembly mounted to the circuit board over the LED and configuredto receive the light emitted from the LED and reduce the angular CCTdeviation of the light received from the LED to make a color temperatureof the light received from the LED more uniform, and an elastomerencapsulating at least part of the circuit board that is separate anddistinct from the lens assembly.

In some embodiments, the lens assembly is configured to mix the lightreceived from the LED. In some embodiments, the lens assembly isconfigured to collimate the mixed light to form a beam.

In some embodiments, the lens assembly comprises a lens disposed overthe LED having a bottom surface that faces the circuit board, a topsurface opposite the bottom surface, and a lateral surface between thetop surface and the bottom surface. In some embodiments, the elastomerdoes not contact at least part of the lateral surface of the lens. Insome embodiments, the top surface of the lens is flat (or approximatelyflat). In some embodiments, the top surface of the lens is curved. Insome embodiments, at least a portion of the lateral surface of the lensis configured to provide total internal reflection (TIR) of at leastsome light. In some embodiments, the lens comprises a recess that facesthe LED. In some embodiments, the recess is configured to provide an airgap between a surface of the LED through which light is emitted and thelens. In some embodiments, at least part of the recess is textured tomix light received from the LED. In some embodiments, the lens assemblycomprises a light scattering element disposed between the LED and thelens. In some embodiments, the lens assembly comprises a reflectorhaving a reflective surface that faces the lens. In some embodiments,the reflective surface of the reflector provides specular reflection,diffusive reflection, or a combination thereof. In some embodiments, thereflective surface faces the lateral surface of the lens and isconfigured to reflect light from the lateral surface of the lens backinto the lens. In some embodiments, the lens assembly comprises a basemounted to the circuit board and wherein the reflector and the lens areconfigured to couple to the base.

In some embodiments, the LED comprises a phosphor converted LED. In someembodiments, the phosphor converted LED is a white phosphor convertedLED. In some embodiments, the circuit board is a flexible printedcircuit board. In some embodiments, the lighting device comprises aconnector mounted to the circuit board and electrically coupled to theLED. In some embodiments, the connector is configured to electricallycouple the LED to another device such as another lighting device or apower adapter. In some embodiments, the elastomer comprises silicone.

In some embodiments, the lighting device is configured to mount to aguide rail or a walking path to illuminate the walking path. In someembodiments, the lighting device is configured to mount to a ceiling ora ledge to illuminate at least one member selected from the groupconsisting of: a ceiling, a wall, and a billboard.

In some embodiments, the lighting device may be implemented as a striplighting device having a length (e.g., approximately six inches), awidth that is less than the length (e.g., approximately one inch), and aheight that is less than the width (e.g., approximately half an inch).In some embodiments, the strip lighting device comprises a plurality ofLEDs that are spaced along the length of the strip lighting device(e.g., the LEDs may be spaced apart by approximately one inch).

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects and embodiments will be described with reference to thefollowing figures. It should be appreciated that the figures are notnecessarily drawn to scale. In the drawings, each identical or nearlyidentical component that is illustrated in various figures isrepresented by a like numeral. For purposes of clarity, not everycomponent may be labeled in every drawing.

FIG. 1A shows a top view of an example lighting system, according tosome embodiments of the technology described herein;

FIG. 1B shows a bottom view of the example lighting system of FIG. 1A,according to some embodiments of the technology described herein;

FIG. 2A shows a front view of the example lighting system of FIG. 1A,according to some embodiments of the technology described herein;

FIG. 2B shows a rear view of the example lighting system of FIG. 1A,according to some embodiments of the technology described herein;

FIG. 3 shows a cross-sectional view of the example lighting system ofFIG. 1A, according to some embodiments of the technology describedherein;

FIG. 4 shows an exploded view of an example lens assembly, according tosome embodiments of the technology described herein;

FIG. 5A shows a cross-sectional view of an example lens, according tosome embodiments of the technology described herein;

FIG. 5B shows a perspective view of an example reflector configured tobe used with the lens shown in FIG. 5A, according to some embodiments ofthe technology described herein;

FIG. 6A shows a side view of an example asymmetric lens and reflectorassembly, according to some embodiments of the technology describedherein;

FIG. 6B shows an example light distribution provided by the exampleasymmetric lens and reflector assembly in FIG. 6A, according to someembodiments of the technology described herein;

FIG. 7A shows a scatter plot illustrating the angular correlated colortemperature (CCT) deviation exhibited by three different white phosphorconverted LEDs, according to some embodiments of the technologydescribed herein;

FIGS. 7B and 7C show scatter plots illustrating the angular CCTdeviation exhibited by a white phosphor converted LED with a lensassembly configured to reduce the angular CCT deviation, according tosome embodiments of the technology described herein;

FIG. 8A shows an example lighting system in a railway lightingapplication, according to some embodiments of the technology describedherein;

FIG. 8B shows an example lighting system in a ceiling lightingapplication, according to some embodiments of the technology describedherein;

FIG. 8C shows an example lighting system in a pathway lightingapplication, according to some embodiments of the technology describedherein;

FIG. 8D shows an example lighting system in a pathway lightingapplication, according to some embodiments of the technology describedherein;

FIG. 8E shows an example lighting system in a wall lighting application,according to some embodiments of the technology described herein;

FIG. 8F shows an example lighting system in a billboard lightingapplication, according to some embodiments of the technology describedherein; and

FIG. 8G shows an example lighting system in a ceiling lightingapplication, according to some embodiments of the technology describedherein.

DETAILED DESCRIPTION

As discussed above, some LEDs have a phosphor coating that converts aportion of the light from the LED into light of another color (aphosphor converted LED). Phosphor converted LEDs may be capable ofproducing light with a broad spectrum such as white light. For example,a white phosphor converted LED may be formed by coating a blue LED witha yellow phosphor layer. Thereby, a portion of the blue light from theblue LED is converted into yellow light so as to create white light.

The inventors have appreciated that phosphor converted LEDs, such aswhite phosphor converted LEDs, typically exhibit angular correlatedcolor temperature (CCT) deviation. Angular CCT deviation may be a shiftin a color temperature of light that is a function of the emission angleof the light. For example, the light pattern produced by a whitephosphor converted LED on a surface may appear white near the center ofthe light pattern and off-white near the edges of the light pattern. Ascatter plot 700A in FIG. 7A illustrates the angular CCT deviationproduced by white phosphor converted LEDs. The scatter plot 700Acomprises a set of points for each of three different white phosphorconverted LEDs plotted in a CIE 1931 color space and a MacAdam ellipse702 for a color temperature of 2700 degrees Kelvin (K). Each set ofpoints is representative of the color coordinates of light from aparticular white phosphor converted LED at different emission angles.The MacAdam ellipse 702 may be representative of the set of colorcoordinates that will appear to be 2700 K to a human observer. As shownin FIG. 7A, none of the three different white phosphor converted LEDsproduce light within the MacAdam Ellipse 702 across the entire range ofemission angles. Thereby, the angular CCT deviation may be visible to ahuman observer.

The inventors have devised new techniques to correct the angular CCTdeviation of light from phosphor converted LEDs to produce light with amore uniform color temperature across a range of emission angles. Insome embodiments, the angular CCT deviation of light from phosphorconverted LEDs may be reduced using a lens assembly disposed above theLED. The lens assembly may be configured to mix the light from the LEDto make the color temperature of the light more uniform and collimatethe mixed light to produce a beam. FIGS. 7B and 7C show scatter plotsillustrating the angular CCT deviation produced by lighting devices withsuch a lens assembly disposed over a phosphor converted LED. Inparticular, FIGS. 7B and 7C shows the x and y coordinates, respectively,in a CIE 1931 color space of light emitted from the lens assembly acrossa range of emission angles. As shown, the x color coordinate of thelight remains between 0.435 and 0.445 across the plotted range ofemission angles. Similarly, the y color coordinate of the light remainsbetween 0.41 and 0.42 across the plotted range of emission angles.

In addition, the inventors have devised new techniques to integratelenses into LED lighting devices at least partially encapsulated with anelastomer. The inventors have appreciated that the elastomerencapsulating LED lighting devices may have a similar (or same)refractive index as the lens thereby diminish the efficacy of the lens.For example, light may simply pass from a surface of the lens into theelastomer without being reflected or otherwise redirected because boththe lens and the elastomer have a similar (or same) refractive index.Accordingly, the inventors have devised LED lighting devices thatcomprise a gap (e.g., an air gap) between the elastomer encapsulatingthe LED lighting device such that the refractive index of the media incontact with the lens is different (e.g., lower) than that of the lens.Thereby, the surfaces of the lens may be constructed to reflect orotherwise redirect light.

Accordingly, some aspects of the present disclosure relate to lightingsystems that provide light with a uniform (or approximately uniform)color temperature across a range of emission angles using lensassemblies. A lens assembly may be a set of one or more componentscomprising at least one lens. Example components apart from the at leastone lens that may be included in a lens assembly include reflectors,scattering elements, mirrors, and structural elements to hold a lens (orany other component of the lens assembly) in place.

The lighting systems may comprise a circuit board onto which variouselectrical components may be mounted. The circuit board may be, forexample, an FR4 printed circuit board (PCB). The circuit board may beflexible to allow the lighting system to bend without breaking and,thereby, ease installation of the lighting system. An LED may be mountedto the circuit board and configured to emit light. The light emittedfrom the LED may have an angular CCT deviation such as a phosphorconverted LED.

The lighting system may comprise a lens assembly disposed over the LEDto receive light from the LED and reduce the angular CCT deviation ofthe received light. For example, the lens assembly may mix the lightreceived from the LED to make the color temperature more uniform andcollimate the mixed light to form a beam. The lens assembly may comprisea lens and a reflector disposed over the LED. The lens may receive lightfrom the LED through a bottom surface and provide light through a topsurface. The lens may be, for example, a monolithic lens constructedfrom any of a variety of materials such as silicone, glass, and/or aplastic (e.g., acrylic or polycarbonate). The lens may omit scatteringparticles and/or phosphors. The reflector may comprise a reflectivesurface that faces the lens and reflects light that leaves a lateralsurface of the lens back into the lens. Thereby, the light in the lensmay be emitted through the top surface of the lens. The reflectivesurface may be configured to provide diffuse and/or specular reflection.The reflector may be, for example, a monolithic reflector constructedfrom a plastic (e.g., acrylic or polycarbonate) coated in a materialsuch as a paint or a metal to achieve the desired reflection (e.g.,diffuse and/or specular reflection).

The lighting system may comprise an elastomer that at least partiallyencapsulates the circuit board. For example, the elastomer may be incontact with the circuit board and one or more components of the lensassembly such as the reflector. The elastomer not be in contact with allof the components of the lens assembly. For example, the elastomer maynot be in contact with the lens so as to provide a gap (e.g., an airgap) between the lens and the elastomer. The elastomer may protect thecircuit board and/or electronic components mounted to the circuit boardfrom the environment. Example elastomers include silicones and rubbers.The elastomer encapsulating at least part of the circuit board may beseparate and distinct from the other components of the lighting systemsuch as the lens and/or the entire lens assembly.

It should be appreciated that the embodiments described herein may beimplemented in any of numerous ways. Examples of specificimplementations are provided below for illustrative purposes only. Itshould be appreciated that these embodiments and thefeatures/capabilities provided may be used individually, all together,or in any combination of two or more, as aspects of the technologydescribed herein are not limited in this respect.

Example Lighting Systems

FIGS. 1A and 1B show top and bottom views, respectively, of an examplelighting system 100. As shown, the lighting system 100 is constructed asa strip lighting system that comprises a plurality of electricallycoupled lighting devices 102. Thereby, the length of the lighting system100 may be customized by adding (or removing) lighting devices 102. Eachof the lighting devices 102 may comprise LEDs that are electricallycoupled to a connector 104. In turn, the connector 104 may electricallycouple to an external device such as another lighting device 102 or apower adapter. The LEDs may receive power from the external device viathe connector 104 and emit light. The connector 104 may be implementedas a male or female connectors as shown below in FIGS. 2A and 2B.

The lighting device 102 may comprise a plurality of lens assemblies 106disposed over the LEDs. The lens assemblies 106 may change at least onecharacteristic of the light emitted from the LEDs. For example, the LEDsmay be phosphor converted LEDs that emit light with an angular CCTdeviation. In this example, the lens assemblies 106 may receive lightfrom the LED and make the color temperature of the light more uniform.Additionally (or alternatively), the lens assembly 106 may adjust alight distribution pattern of the LED. For example, the lens assembly106 may create a circular beam of light or an oblong beam of light.

FIGS. 2A and 2B show front and rear views, respectively, of the lightingdevice 102. As shown, the lighting device 102 comprises a tray 210 witha channel 211 into which a circuit board 208 may be inserted. Thecircuit board 208 may be, for example, a flexible PCB to allow thelighting device 102 to bend without breaking. Once the circuit board 208has been inserted into the tray 210, potting material 212 may be addedto the lighting device 102 to fill the tray 210. Thereby, the pottingmaterial 212 may be contact with the circuit board 208, the tray 210,and/or the connector 104 (implemented as female connector 201 or maleconnector 202). The potting material 212 and/or the tray 210 may beconstructed from an elastomer. Thereby, the circuit board 208 may be atleast partially encapsulated with an elastomer. For example, both thepotting material 212 and the tray 210 may be constructed from silicone.It should be appreciated that the potting material 212 may have adifferent material composition than the channel 210.

The circuit board 208 may be electrically coupled to other componentsusing the connector 104 that may be implemented as a female connector201 or a male connector 202. The female connector 201 comprises a cavity204 with multiple contacts 206. The cavity 204 may be configured toreceive a plug of a corresponding male connector (e.g., male connector202). The male connector 202 may comprise a plug 203 with contacts 206disposed on a bottom surface of the plug 203. The plug 203 may beconstructed to be inserted into a female connector (e.g., femaleconnector 201).

FIG. 3 shows a cross-section of the lens assembly 106 in the lightingdevice 102. As shown, the lens assembly 106 comprises a lens 310 and areflector 306 disposed over an LED 302 mounted to the circuit board 208.The lens 310 comprises a recess that is configured to receive the LED302 and provide a gap 304 (e.g., an air gap) between the LED 302 and thelens 310. The lens 310 may receive the light from the LED 302 and directthe light towards the reflector 306. In turn, the reflector 306 may beconfigured to reflect light that leaves a lateral surface of the lens310 back into the lateral surface of the lens 310. The reflector 306 maybe constructed to provide a gap 308 between the lateral surface of thelens 310 and a reflective surface of the reflector 306. The gap 308 maybe left unfilled to form an air gap. Alternatively, the gap 308 may befilled with a material to keep debris from entering the gap 308. In someembodiments, the material employed to fill the gap 308 may have arefractive index that is lower than the refractive index of the lens 310to operate similarly to an air gap. In other embodiments, the materialemployed to fill the gap 308 may have the same (or similar) refractiveindex as the lens 310. In yet other embodiments, the material employedto fill the gap 308 may have a greater refractive index than the lens310. Suitable materials to fill the gap 308 include elastomers such assilicone.

It should be appreciated that various alterations may be made to thecross-section of the lens assembly 106 in FIG. 3 without departing fromthe scope of the present disclosure. For example, the reflector 306 maybe removed and the lateral surface of the lens may be configured toreflect light back into the lens without the reflector 306.Alternatively, the potting material 212 may not be in contact with atleast part of an opposite surface of the reflector 306 that faces awayfrom the lens 310. Thereby, there may be a gap between the pottingmaterial 212 and the reflector 306.

Example Lens Assemblies

As discussed above, a lens assembly (e.g., lens assembly 106) may bedisposed above an LED to adjust one or more characteristics of the lightemitted from the LED. An example of such a lens assembly is shown inFIG. 4 by an exploded view of a lens assembly 400. As shown, the lensassembly 400 is disposed over an LED 402 and comprises a scatteringelement 404, a base 406, a reflector 408, and a lens 410. The lensassembly 400 may be constructed to receive light from the LED, mix thereceived light to make the color temperature more uniform, and collimatethe light to form a beam. For example, the scattering element 404, thelens 410, and/or the reflector 408 may scatter light to cause mixingand, thereby, make the color temperature more uniform. In someembodiments, the light that leaves a lateral surface of the lens 410(e.g., as a result of the mixing) may be reflected back into the lens410 towards a top surface of the lens 410. Thereby, the mixed light maybe collimated so as to form the beam.

The LED 402 may be a semiconductor device that is configured to emitlight (e.g., LED 302). The LED 402 may be configured to emit light withan angular CCT deviation such as a phosphor converted LED. The LED 402may be mounted to a circuit board (e.g., circuit board 208).

The base 406 may be constructed to hold the lens assembly 400 in placeover the LED 402. For example, the base 406 may be mounted to the samecircuit board that the LED 402 is mounted to. The base 406 may compriseone or more tabs 412 to facilitate mounting the base 406 on a circuitboard. For example, the tabs 412 may be affixed to the circuit boardusing through holes in the circuit board.

The base 406 may serve as an anchor point for one or more othercomponents of the lens assembly (e.g., the scattering element 404, thereflector 408, and/or the lens 410). The base 406 may comprise a ridge414 to couple to the one or more other components of the lens assembly400. For example, the ridge 414 may have an outer lip that the reflector408 may engage to form a snap-fit. Additionally (or alternatively), theridge 414 may have an inner lip that the lens 410 may engage to form asnap-fit.

The scattering element 404 may be disposed between the LED 402 and thelens 410 and configured to scatter light from the LED 402. Thescattering element 404 may be constructed by dispersing a plurality ofscattering particles in a material. For example, the scattering element404 may be constructed by distributing a plurality of titanium dioxide(TiO₂) particles in silicone. The scattering element 404 may beimplemented in any of a variety of shapes and sizes. For example, thescattering element 404 may be implemented as a block or a sheet. Thescattering element 404 may comprise one or more textured surfaces toimprove light transmission through the scattering element 404. Forexample, a surface of the scattering element 404 that faces the LED 402may be textured.

The lens 410 may be a refractive element that receives light from theLED 402 and/or from the scattering element 404. The lens 410 may be, forexample, a monolithic lens constructed from silicone, glass, and/orplastic.

The reflector 408 may be a reflective element that is configured toreflect light (e.g., using dispersive reflection and/or specularreflection) from a lateral surface of the lens 410 back into the lens410. The reflector 410 may be, for example, a monolithic reflectorconstructed from a plastic such as acrylic and polycarbonate coated in amaterial such as paint or a metal (e.g., aluminum, copper, and nickel).

The lens 410 and reflector 408 may be constructed in any of variety ofways. An example implementation of the lens 410 and reflector 408 isshown in FIGS. 5A and 5B by lens 500 and reflector 520, respectively. Asshown in FIG. 5A, the lens 500 comprises a recess 502, a recess surface504, a bottom surface 506, a lateral surface 508, a top surface 510, andan inner surface 512.

The recess 502 may be constructed to receive an LED (e.g., LED 402)and/or a scattering element (e.g., scattering element 404). The recess502 may be deep enough to provide an air gap between the LED and therecess surface 504. The recess surface 504 may be textured to scatterlight and, thereby, facilitate mixing of the received light from theLED.

The bottom surface 506 may be in contact with a circuit board (e.g.,circuit board 208). For example, the bottom surface 506 may be a flatsurface that rests against the circuit board.

The inner surface 512 may be in contact with air. Thereby, the innersurface 512 may not be in contact with potting material (e.g., pottingmaterial 212). The inner surface 512 may be configured to reflect lightreceived through the recess surface 504 towards the lateral surface 508of the lens 500. For example, the inner surface 512 may be constructedsuch that light received through the recess surface 504 strikes theinner surface 512 at an angle that is greater than the critical anglefor total internal reflection (TIR).

The lateral surface 508 may be in contact with air or another media(e.g., a material with a lower refractive index than the lens 500). Thelateral surface 508 may be configured to allow light to pass into andout of the lens 500. For example, light may leave a lateral surface 508and be reflected back into the lens 500 by an inner surface 522 of thereflector 520. Alternatively (or additionally), the lateral surface 508of the lens may be configured to reflect light towards the top surface510 of the lens 500. For example, the lateral surface 508 may beconstructed such that light strikes the lateral surface 508 at an anglethat is greater than the critical angle for TIR.

The lens 500 may be received by the reflector 520, as shown in FIG. 5B,that comprises an inner surface 522, an outer surface 524, a bottom edge526, and a top edge 528. The top edge 528 and the bottom edge 526 may beproximate the top surface 510 and the bottom surface 506, respectively,of the lens 500 when the lens 500 is placed in the reflector 520. Theinner surface 522 may be a reflective surface that reflects light fromthe lateral surface 508 of the lens 500 back into the lens 500. Theinner surface 522 may be configured to provide specular and/or diffusivereflection. For example, a portion of the inner surface 522 may beconfigured to provide diffusive reflection to enhance mixing of thelight to make the color temperature more uniform. The outer surface 524may be a reflective or non-reflective surface opposite the inner surface522. The outer surface 524 may (or may not) be in contact with a pottingmaterial (e.g., potting material 212) in the lighting system.

It should be appreciated that various alterations may be made to thelens 500 and the reflector 520 without departing from the scope of thepresent disclosure. The shape of the top surface 510 of the lens 500and/or the top edge of the reflector 520 may be adjusted to change thedistribution of light from the lens 500. For example, the top surface510 of the lens 500 and/or the top edge of the reflector 520 may beasymmetrical in shape (e.g., elliptical) to form different distributionsof light. An example asymmetrical lens and reflector is shown in FIG. 6by lens 600 in a reflector 620. As shown, the lens 600 has a top surface610 that is curved to create an asymmetric light distribution, a bottomsurface 606 opposite the top surface that may face a circuit board, arecess 602 to receive an LED, a lateral surface 608 that faces thereflector 620. The asymmetric light distribution created by the lens 600and the reflector 620 in the Z-Y plane is shown in FIG. 6B. As shown,the lens 600 and the reflector 620 provide light at angles ranging from0 degrees (°) to 80°. Table 1 below shows the relative luminanceprovided by the lens 600 and the reflector 620 in different regions ofthe Z-Y plane.

TABLE 1 Relative Luminance for various regions in Z-Y Plane Angle on Z-YPlane Relative Luminance [%]  0°-10° 5.0 10°-45° 28.4 45°-80° 40.1 >80°10.0  <0° 16.6

Example Lighting Applications

The lighting devices described above may be employed in any of a varietyof lighting applications. FIGS. 8A-8G show various lighting applicationsthat may employ the lighting devices and/or systems described hereinsuch as lighting system 100. The various lighting applications includerailway lighting applications, ceiling lighting applications, pathwaylighting applications, wall lighting applications, and billboardlighting applications. In each of the lighting applications describedbelow, a lighting device may be mounted to a structure such as a wall, aceiling, a ledge, a guide rail, or a lighting post using an adhesive.For example, an adhesive backing may be applied to the bottom of thelighting device (e.g., the surface of lighting device 102 shown in FIG.1B) and the bottom of the lighting device may be pressed against thestructure to mount the lighting device. Thereby, the adhesive may holdthe lighting device in place on the structure.

FIG. 8A shows an example lighting device 802A in a railway lightingapplication. As shown, the lighting device 802A is disposed over arailway 806 to illuminate the railway 806. The lighting device 802A ismounted to a light post 808 that is proximate the railway 806. Thelighting device 802A may be configured to provide a circular or oblonglight beam 804A to illuminate the railway 806. For example, the lightingdevice 802A may employ the lens 500 and/or reflector 520 to create thecircular or oblong light beam 804A.

FIG. 8B shows an example lighting device 802B in a ceiling lightingapplication. As shown, the lighting device 802B may be mounted on aledge 814 that is attached to a wall 812. The lighting device 802B maybe configured to provide an asymmetric light beam 804B that illuminatesa ceiling 810. For example, the lighting device 802B may employ the lens600 and/or reflector 620 to create the asymmetric light beam 804B.

FIG. 8C shows an example lighting device 802C in a pathway lightingapplication. As shown, the lighting device 802C may be mounted to aguide rail 818. The lighting device 802C may be configured to provide anasymmetric light beam 804C that illuminates a walking path 816. Forexample, the lighting device 802C may employ the lens 600 and/orreflector 620 to create the asymmetric light beam 804C.

FIG. 8D shows an example lighting device 802D in a pathway lightingapplication. As shown, the lighting device 802D may be mounted on thewalking path 816 and/or the ground proximate the walking path 816. Thelighting device 802D may be configured to provide an asymmetric lightbeam 804D that illuminates the walking path 816. For example, thelighting device 802D may employ the lens 600 and/or reflector 620 tocreate the asymmetric light beam 804D.

FIG. 8E shows an example lighting device 802E in a wall lightingapplication. As shown, the lighting device 802E may be mounted on theceiling 810. The lighting device 802E may be configured to provide anasymmetric light beam 804E that illuminates a wall 812. For example, thelighting device 802E may employ the lens 600 and/or reflector 620 tocreate the asymmetric light beam 804E.

FIG. 8F shows an example lighting device 802F in a billboard lightingapplication. As shown, the lighting device 802F may be mounted on theceiling 810. The lighting device 802F may be configured to provide anasymmetric light beam 804F that illuminates a billboard 818 on a wall812. For example, the lighting device 802F may employ the lens 600and/or reflector 620 to create the asymmetric light beam 804F.

FIG. 8G shows an example lighting device 802G in a ceiling lightingapplication to create a knife edge lighting effect. As shown, thelighting device 802G may be mounted on a ledge 814. The lighting device802G may be configured to provide an asymmetric light beam 804G thatilluminates the ceiling 810. For example, the lighting device 802G mayemploy the lens 600 and/or reflector 620 to create the asymmetric lightbeam 804G.

Various aspects of the present disclosure may be used alone, incombination, or in a variety of arrangements not specifically discussedin the embodiments described in the foregoing and is therefore notlimited in its application to the details and arrangement of componentsset forth in the foregoing description or illustrated in the drawings.For example, aspects described in one embodiment may be combined in anymanner with aspects described in other embodiments.

Use of ordinal terms such as “first,” “second,” “third,” etc., in theclaims to modify a claim element does not by itself connote anypriority, precedence, or order of one claim element over another or thetemporal order in which acts of a method are performed, but are usedmerely as labels to distinguish one claim element having a certain namefrom another element having a same name (but for use of the ordinalterm) to distinguish the claim elements.

The terms “approximately,” “about,” and “substantially” may be used tomean within ±20% of a target value in some embodiments, within ±10% of atarget value in some embodiments, within ±5% of a target value in someembodiments, and yet within ±2% of a target value in some embodiments.The terms “approximately,” “about,” and “substantially” may include thetarget value.

Also, the phraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. The use of“including,” “comprising,” or “having,” “containing,” “involving,” andvariations thereof herein, is meant to encompass the items listedthereafter and equivalents thereof as well as additional items.

Having described above several aspects of at least one embodiment, it isto be appreciated various alterations, modifications, and improvementswill readily occur to those skilled in the art. Such alterations,modifications, and improvements are intended to be object of thisdisclosure. Accordingly, the foregoing description and drawings are byway of example only.

What is claimed is:
 1. A lighting system, comprising: a lens assemblyincluding a lens having a light output surface being spaced apart alonga central axis from a light input surface, the lens further having alateral surface being spaced apart around the central axis and having afrusto-conical shape extending between the light input and outputsurfaces of the lens, the lens being configured for causing some lightpassing into the lens through the light input surface to be divertedtoward the lateral surface; a light source being located adjacent to thelight input surface of the lens, the light source including asemiconductor light-emitting device and being configured for generatinglight being directed through the light input surface into the lens; areflector having another frusto-conical shape, the reflector beingspaced apart around the central axis and extending between the lightinput and output surfaces of the lens, the reflector having a reflectivesurface that faces toward the lateral surface of the lens, the reflectoralso having an opposite surface that faces away from the lateral surfaceof the lens; and a potting material facing toward the opposite surfaceof the reflector, the potting material being spaced apart from theopposite surface of the reflector so as to form a gap.
 2. The lightingsystem of claim 1, wherein the light source includes the semiconductorlight-emitting device as being a phosphor-converted semiconductorlight-emitting device.
 3. The lighting system of claim 1, wherein thelens has an inner surface forming a frusto-conical cavity extending fromthe light output surface along the central axis into the lens, the innersurface being for causing some light passing into the lens through thelight input surface to be reflected at the inner surface toward thelateral surface of the lens.
 4. The lighting system of claim 1, whereinthe light input surface has a recess forming a gap between the lens andthe light source, for directing the light from the light source throughthe gap toward the light input surface of the lens.
 5. The lightingsystem of claim 1, wherein the light input surface has a recess formingan air gap between the lens and the light source, for refracting thelight from the light source at a boundary between the air gap and thelens toward a direction being normal to the light input surface.
 6. Thelighting system of claim 1, wherein the potting material includes anelastomer.
 7. The lighting system of claim 1, wherein the reflectivesurface of the reflector is configured to reflect some light from thelateral surface of the lens back into the lens.
 8. The lighting systemof claim 1, wherein the lighting system is a strip lighting systemincluding: another lens assembly including another lens having anotherlight output surface being spaced apart along another central axis fromanother light input surface, the another central axis being spaced apartaway from the central axis, the another lens further having anotherlateral surface being spaced apart around the another central axis andhaving an additional frusto-conical shape extending between the anotherlight input and output surfaces of the another lens, the another lensbeing configured for causing some light passing into the another lensthrough the another light input surface to be diverted toward theanother lateral surface; another light source being located adjacent tothe another light input surface of the another lens, the another lightsource including another semiconductor light-emitting device and beingconfigured for generating light being directed through the another lightinput surface into the another lens; another reflector having yet afurther frusto-conical shape, the another reflector being spaced apartaround the another central axis and extending between the another lightinput and output surfaces of the another lens, the another reflectorhaving another reflective surface that faces toward the another lateralsurface of the another lens, the another reflector also having anotheropposite surface that faces away from the another lateral surface of theanother lens; and another potting material facing toward the anotheropposite surface of the another reflector, the another potting materialbeing spaced apart from the another opposite surface of the anotherreflector so as to form another gap.
 9. The lighting system of claim 1,wherein a refractive index of the lens is similar to another refractiveindex of the potting material.
 10. The lighting system of claim 1,wherein a refractive index of the lens is higher or lower than anotherrefractive index of the potting material.
 11. A lighting system,comprising: a lens assembly including a lens having a light outputsurface being spaced apart along a central axis from a light inputsurface, the lens further having a lateral surface being spaced apartaround the central axis and having a frusto-conical shape extendingbetween the light input and output surfaces of the lens, the lens beingconfigured for causing some light passing into the lens through thelight input surface to be diverted toward the lateral surface; a lightsource being located adjacent to the light input surface of the lens,the light source including a semiconductor light-emitting device andbeing configured for generating light being directed through the lightinput surface into the lens; a reflector having another frusto-conicalshape, the reflector being spaced apart around the central axis andextending between the light input and output surfaces of the lens, thereflector having a reflective surface that faces toward the lateralsurface of the lens, the reflector also having an opposite surface thatfaces away from the lateral surface of the lens; wherein the reflectivesurface of the reflector is spaced apart from the lateral surface of thelens forming a gap; and wherein the light input surface has a recessforming a gap between the lens and the light source, for directing thelight from the light source through the gap toward the light inputsurface of the lens.
 12. The lighting system of claim 11, wherein thelight source includes the semiconductor light-emitting device as being aphosphor-converted semiconductor light-emitting device.
 13. The lightingsystem of claim 11, wherein the lens has an inner surface forming afrusto-conical cavity extending from the light output surface along thecentral axis into the lens, the inner surface being for causing somelight passing into the lens through the light input surface to bereflected at the inner surface toward the lateral surface of the lens.14. The lighting system of claim 11, wherein the recess in the lightinput surface forms the gap as an air gap between the lens and the lightsource, for refracting the light from the light source at a boundarybetween the air gap and the lens toward a direction being normal to thelight input surface.
 15. The lighting system of claim 11, wherein thepotting material includes an elastomer.
 16. The lighting system of claim11, wherein the reflective surface of the reflector is configured toreflect some light from the lateral surface of the lens back into thelens.
 17. The lighting system of claim 11, wherein the lighting systemis a strip lighting system including: another lens assembly includinganother lens having another light output surface being spaced apartalong another central axis from another light input surface, the anothercentral axis being spaced apart away from the central axis, the anotherlens further having another lateral surface being spaced apart aroundthe another central axis and having an additional frusto-conical shapeextending between the another light input and output surfaces of theanother lens, the another lens being configured for causing some lightpassing into the another lens through the another light input surface tobe diverted toward the another lateral surface; another light sourcebeing located adjacent to the another light input surface of the anotherlens, the another light source including another semiconductorlight-emitting device and being configured for generating light beingdirected through the another light input surface into the another lens;another reflector having yet a further frusto-conical shape, the anotherreflector being spaced apart around the another central axis andextending between the another light input and output surfaces of theanother lens, the another reflector having another reflective surfacethat faces toward the another lateral surface of the another lens, theanother reflector also having another opposite surface that faces awayfrom the another lateral surface of the another lens; wherein theanother reflective surface of the another reflector is spaced apart fromthe another lateral surface of the another lens forming another gap. 18.The lighting system of claim 11, wherein a refractive index of the lensis similar to another refractive index of the potting material.
 19. Thelighting system of claim 11, wherein a refractive index of the lens ishigher or lower than another refractive index of the potting material.